The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 07, 1985
Filed:
Dec. 27, 1983
F Harold Hollister, Houston, TX (US);
Danny S Meyer, Richmond, TX (US);
Joy Manufacturing Company, Pittsburgh, PA (US);
Abstract
A valve (10) having an expansible gate assemblage of ported juxtaposed gate and segment members (18, 19) which are movable into sealing engagement with upstream and downstream valve seats (28) about the flow passage (12, 14) in the open and closed conditions of the valve wherein the valve includes pressure relief means which relieves excessive pressure in the valve chamber (11) into the upstream flow passage (12) when the environment in the chamber reaches a preselected temperature with the valve retaining capability of providing an upstream seal in the event of subsequent downstream leakage. The pressure relief means is installed in the segment member (19) of the gate assembly and comprises a passage (43) extending from the port (16) through the segment to the sealing face (25) of the segment member at a location which is exposed to the upstream flow passage (12) in the valve closed condition. The passage (43) includes an enlarged diameter section (44) which is normally plugged by a ball check valve element (42) seated against a shoulder (46) formed in the passage (43) and held thereagainst by a plug (41) of eutectic material and a retainer (47) with an aperture (48) therethrough. The eutectic material is selected to melt at a preselected temperature whereby a pressure build-up in the valve chamber is relieved by unseating the ball check (42) and forcing the molten eutectic material (41) through the apertured retainer (47) into the upstream flow passage (12). In the event of subsequent leakage of the downstream seal to from elsewhere in the valve chamber (11) the upstream line pressure causes the ball check (42) to seat and block the passage (43) such that the valve will again provide an upstream seal.